As stated by Braun in his published United States Patent Application published Sep. 27, 2007 under publication No. 2007/0221385 and entitled Apparatus and Method for Forming Stands, various ground drilling operations are known such as exploring and/or extracting oil from subterranean deposits. The drilling operation is conducted on a drill rig such as illustrated by way of example in FIGS. 1a and 1b comprising a raised drilling platform located above the drilling location. A derrick is provided on the platform to raise, support and rotate a drill string. A drill string includes a drill bit for boring into the ground. As the drilling operation continues, tubular members, commonly referred to as “tubulars” (and referred to herein alternatively as pipes or singles) are connected in an end to end manner to form a drill string. Tubulars are commonly about 30 feet in length and have opposing female and male ends. The ends are threaded in a complementary manner so that opposing male and female ends can be joined together.
The addition of a tubular to an existing drill string is a relatively time consuming and dangerous procedure. Tubulars are provided on a rack from which they are individually rolled onto a horizontal support, such as a catwalk. Both the rack and catwalk are generally located adjacent to the drilling platform with the catwalk being generally positioned perpendicular to the platform. Once on the catwalk, one end of the tubular is attached to a hoist connected either directly or indirectly to the derrick and raised to a vertical position on the drilling platform. The lower end of the tubular is then oriented over the existing drill string and connected to the terminal, surface end of thereof. Following connection of the tubular to the drill string and “torquing” to establish a tight connection, the drilling operation is continued. As indicated above, tubulars are generally about 30 feet (10 m) in length. As such, the frequency of adding tubulars to the drill string is high and, therefore, the efficiency of the drilling operation is hampered. In addition, the above described manipulation of the tubulars often requires manual handling and, therefore, increases the risks to the drill rig personnel.
In order to increase the efficiency of the drilling operation, various methods have been proposed to pre-connect at least two tubulars, to form a “stand”, prior to connection to the drill string. Such a process is often referred to as “standbuilding”. As will be appreciated, such pre-connection step involving two tubulars will reduce by half the number of connections required to be made to the drill string and, therefore, allows the drilling process to continue with fewer interruptions. An example of such a standbuilding procedure is provided in related U.S. Pat. Nos. 6,976,540 and 6,997,265. In these references, a tubular is rolled from a rack onto a ramp positioned adjacent the drilling platform. One end of the tubular is raised by a hoist to a vertical orientation above the drilling platform. The tubular is then inserted into an opening in the drilling platform adjacent to the existing drill string. A further tubular is then vertically hoisted and aligned above the first tubular. The opposing ends are of the two tubulars are then connected together to form a vertical, dual tubular stand. The stand is then raised and secured to the drill string. During formation of the stand, the drilling operation is continued without interruption.
Another example of a standbuilding operation is provided in U.S. Pat. No. 6,705,414. In this reference, a stand is formed on a horizontal catwalk associated with a drilling platform. According to the disclosed method, two pairs of tubulars are positioned end to end on the catwalk. A “bucking machine” is then used to join the two tubulars. The bucking machine includes jaws that grasp and axially rotate the tubulars in opposite directions so as to engage the threads on the respective ends and to torque the connection to the desired value. Two stands are formed in this manner, which are then loaded onto a “trolley”. The trolley, carrying the two stands, is hoisted onto the drill rig platform and oriented vertically. The stands are then removed from the trolley and either connected to the drill string or stored in the vertical position for later connection to the drill string.
In the prior art applicant is also aware of U.S. Pat. Nos. 6,976,540 and 6,997,265 to Berry for his Method and Apparatus for Offline Standbuilding, and U.S. Pat. No. 7,228,919 to Fehres et al. for a Pivoting Pipe Handler for Off-line Make-up of Drill Pipe Joints.
Berry in his patents discloses a method and apparatus for moving pipe on a rig floor between a number of different stations. Pipe handling equipment interacts between an off-floor rack, a preparation opening, a borehole, and a storage area such that tubular joints are loaded onto the drill floor, prepared at the preparation opening, loaded onto or off the storage rack, and connected to a drill string while drilling in simultaneously conducted at the borehole. In one embodiment, joints of drill pipe or other tubulars are moved from the v-door of the rig and delivered into a pair of preparation openings for building stands while drilling activities continue at well center. The system may include a stand building truss device comprising a vertical truss mounted inside the derrick in a position where it can access the v-door pick-up point and preparation openings using a powered slew about a vertical access. Other embodiments are taught such as providing an iron roughneck for making up connections between the tubulars which roughneck has an operating reach which intersects the pipe handling device. In another embodiment, the pipe handling device has a reach which intersects through a v-door such that the pipe handling device may hoist tubulars from outside of the drilling platform, such as from an external storage area via a tubular ramp. In another of several alternative embodiments, a robotic arm is provided which is mounted in generally in the derrick to provide for moving drill pipe and drill collars between the well center or stand building location to the setback position and back again. In one disclosed embodiment, the pipe handling device is taught to include a vertically extending frame and a vertically aligned gripping device mounted thereon provided adjacent to a preparation opening and a vertical or v-door provided in the side of the derrick for access to areas off the drill floor such as an external catwalk and a tubular access ramp.
Fehres et al discloses an apparatus and method for use in the off-line make-up of drill pipes stands on drilling rigs. A section of a v-door ramp which is attached to the drilling rig structure is fixed and an adjacent section is pivotable between its position adjacent the fixed v-door ramp section and a lowered position wherein the pivotable section is lower to the vertical. One or more joints of drill pipe are loaded onto the pivotable section and clamp thereon so that the joints of drill pipe may then be rotated to the vertical. An off-line drill pipe elevator elevates joints of drill pipe and, prior to placing the pipe stand for storage into a racking board, the joints are made up into a pipe stand by the use of an off-line roughneck.